1. Field of the Invention
The invention relates to a business based model for the diagnosis of BPPV and the sale of devices for the diagnosis and treatment of BPPV.
2. Background
BPPV
BPPV is classically used to refer to vertigo caused by loosened otoconia crystals in the posterior semicircular canal, the most common inner ear semicircular canal effected by loosened otoconia. To those trained in the art, given the current understanding of the pathophysiology of BPPV, the definition of BPPV is positional vertigo caused by loosened crystals in any of the membranous semicircular canals moving in response to gravity. This more generalized definition is the one used in this application. I will refer to classic posterior semicircular canal positional vertigo as posterior BPPV or PBPPV, horizontal BPPV as HBPPV and superior semicircular canal BPPV as SBPPV.
Pathophysiology of BPPV
BPPV is caused by 1) naturally occurring calcium carbonate crystals becoming dislodged and falling from their normally occurring position on the utricular macula and 2) a significant number of the crystals coming to be located in a membranous semicircular canal. When the patient places the head such that a particular semicircular canal is vertical, the loosened crystal(s) causes motion of the rotation sensor causing the patient to sense vertigo. These symptoms typically resolve when the loosened crystal dissolves in the surrounding endolymphatic fluid. If the loosened crystals can be moved out of the affected membranous SCC then the patient symptoms are markedly decreased or resolved.
Incidence of BPPV
90 million Americans (42% of the population) will experience vertigo some time in their life. Approximately three million people of the 250 million people in the US suffer some vertigo each year. Vertigo is the most common physician visit diagnosis in patients over 65 years of age. Seventeen percent of patients who have dizziness have benign paroxysmal positional vertigo (BPPV). According to Fife1, 91% of the BPPV patients were thought to have involvement of the posterior semicircular canal, 6% involvement of the horizontal canal (7.8% according to Takegoshi2), and 3% involvement of the superior (or anterior) semicircular canal. This application is directed to a new method for the diagnosis and treatment of posterior BPPV and the treatment of benign paroxysmal positional vertigo in the horizontal and superior semicircular canals.
Posterior BPPV
PBBPV""s hallmark is vertigo when the patient moves into the affected ear downward position. The patient may also have symptoms of dizziness with looking up, or looking down. The diagnosis is clinically confirmed by placing the patient in the affected ear down position and watching a characteristic rotary motion of the eyes. Although some cases of BPPV follow head trauma, most cases have spontaneous onset of unknown origin. The natural history of positional vertigo is one of spontaneous remission, typically over 6 weeks. Recurrence is common and can last from weeks to months.
One ear is usually involved but reports of up to 15% of bilateral ear involvement have been made.
PBPPV is caused when a significant number of the loosened crystals come to be located within the posterior semicircular canal.
PBPPV Treatments
In 1980 Brandt Daroff3 described a sequence of maneuvers in which the patient sat on the edge of a bed/surface and laid down laterally with the head touching the surface. After the symptoms resolved, the patient sat up and laid down on the opposite side. This was done every three hours while awake and terminated after two symptom-free days. This maneuver was thought to free the otolithic debris which was attached to the cupula of the posterior semicircular canal ampulla.
Semont4 described what he called a Liberatory maneuver in which the patient was rapidly moved from a sitting position to the provoking position and kept in that position for 2-3 minutes. The patient was then rapidly brought up through the sitting position to lie on the contralateral side with the head turned downward 45 degrees. The therapist maintained the alignment of the neck and head on the body. The patient stayed in this second position for 5 minutes. In this second position the vertigo reappears and resolves. After the vertigo resolved the patient was slowly returned to a seated position and remained vertical for 48 hours thereafter. This technique was thought to work by causing the debris within the posterior semicircular canal to fall out of the canal.
Norre5,6,7 described the use of vestibular rehabilitation maneuvers for the treatment of BPPV. Some support for this compared to the liberatory and Epley canalith repositioning maneuvers (CRM) has been expressed.
Epley8,9 studied and refined Semont""s Liberatory maneuver4. Epley""s maneuver is now thought to be the most effective technique for moving the crystals out of the posterior membranous SCC (posterior canalith repositioning maneuver).
This maneuver is defined by Epley8,9 as being made up of 6 positions: Start, and Positions 1, 2, 3, 4, and 5. The start position is the patient seated upright in an examination chair or on a table looking forward with the operator behind the patient and a mastoid oscillator applied to the effected ear behind the ear (ipsilateral mastoid area). In position 1, the patient is lying supine with the neck extended 20 degrees and the head turned 45 degrees toward the effected ear downward position. While in position 1, with the neck continuing to be extended 20 degrees, the head is turned 90 degrees toward the unaffected ear i.e. 45 degrees from vertical in the direction of the unaffected ear into postion 2. To go from position 2 to position 3, the neck is kept extended 20 degrees, the patient rolls onto the unaffected ear side of his or her body and the head is rolled into position 3. In position three, the head (nose) is pointed 135 degrees downward, affected ear upward, from the supine position. Keeping the head (nose) in the 135 degrees downward position, the patient is brought up to a sitting position, position 4. In position 5, the head is turned forward and the chin downward 20 degrees. Each position is held until the induced nystagmus stops (xe2x80x9capproaches terminationxe2x80x9d).
Harvey10 described a modification of Semont""s Liberatory maneuver which is very similar in its positions to that of Epley""s canalith repositioning maneuver.
Katsarkas11 showed a modification of the Epley canalith repositioning maneuver which he developed. In his maneuver, after the Epley position 3, he extends the neck as far as is reasonably possible to allow (he believes) the otoconia to fall into and through the common crus portion of the posterior semicircular canal crystal removal route.
Best PBPPV Treatment Observations
One skilled in the art will recognize that the head maneuver to relieve PBPPV can be done in an large (theoretically infinite) number of positions. That is, this maneuver could be done using the same head movement sequence outlined by the six positions of the posterior CRP maneuver, but it could be done such that instead of Epley positions 1, 2 and 3 being 90 degrees from the previous positions, the maneuver could be divided into five positions each 45 degrees from the position that preceded it and 45 degree from the position that follows it. If resolution of clinical vertigo caused by each position was used as the indicator to proceed to the next position, this theoretical five position maneuver would be as effective in the resolution of BPPV as Epley described in his positions 1, 2, and 3.
In the same way, those skilled in the art will recognize that this rotation of the head could be broken up into many (theoretically an infinite number of) positions. To one skilled in the art, the clinical use of a complex multipositioned maneuver is not clinically possible because of the increased difficulty of correct and consistent positioning when a multipositional maneuver is done manually. This difficulty is increased further for the occasional performer, and markedly more for the less educated and therefore less physiologically understanding occasional performer.
Those skilled in the art recognize that the posterior CRP technique teaches that the Epley positions 1, and 2 are done with the patient""s head extended 20 degrees, the patient""s head is supine and rotated 45 degrees in the effected ear downward position (position one) and rotates toward the unaffected ear downward (into position two) and then into position three with the nose pointed 135 degrees downward from supine (position three).
Theoretically the best sequence of head positions for clearing crystals from the posterior SCC is the position sequence which would cause position two to have the top of the patient""s head directly downward. Positions one and three could be approximately the same as Epley classically described. That is, those skilled in the art will recognize that the greater the patient""s neck is extended (up to 90 degrees) in positions one and two but especially in position two, the greater the chances that the maneuver will effectively clear the symptom-causing crystals from the posterior SCC.
This technique of total patient rotation in the plane of the posterior semicircular canal has been done by Epley8 using a specially build chair and rotation apparatus. Lempert12 performed a similar procedure demonstrating the value of the Epley position one to the Epley position three through an Epely position two in which the patient""s head was pointed directly downward.
Understanding that this head extension greater than 20 degrees and up to 90 degrees makes the maneuver more effective, the current process discloses devices which cause the head extension up to 110 degrees. Based on this teaching, this process includes not only the current configuration but devices which cause the neck to be extended greater than or equal to 10 degrees and up to 110 degrees in the Epley positions one and two.
A Clinical Perspective
The posterior canalith repositioning maneuver technique is currently used by medical and paramedical personnel worldwide for the relief of the symptoms of posterior semicircular canal BPPV. The technique, although easy to do and successful after it is learned, is difficult to successfully teach. The maneuver requires significant experience by the performer to be consistently successful. Attempts to teach the maneuver to patients have been unsuccessful. The devices described herein accurately, consistently and inexpensively provides the user visual feedback as to his head position at any given moment, and provides a path for the user to follow to move his head correctly through the series of positions to accomplish the canalith repositioning maneuver.
Horizontal BPPV
Horizontal BPPV (HBPPV) was first recognized by McClure13 who reported 7 cases with brief episodes of positional vertigo associated with horizontal direction changing positional vertigo. Subsequent studies have reported several variation in the type of nystagmus produced by horizontal canal BPPV, including geotropic and ageotropic direction changing positional nystagmus.
The clinical characteristics are 1) brief episodes of positional vertigo and 2) paroxysmal bursts of horizontal positional nystagmus and 3) lack of any other identifiable central nervous system disorder.
Geotropic horizontal direction changing paroxysmal nystagmus has been found in HBPPV in 90% by Nuti14, and 73% by Takegoshi2 and 84% by Fife1. Takegoshi2 and reported finding BPPV in both the posterior and horizontal semicircular canals. Nuti14, McClure13 and Herdman15 reported finding horizontal canal BPPV after canalith repositioning maneuver for relief of PBPPV.
HBPPV Treatments
Fife1 described three maneuver techniques for treating HBPPV.
The first maneuver was a three-quarter contralateral roll in which the patient""s head was moved in 90 degree increments away from the side with the most intense nystagmus to achieve a 270 degree turn. This maneuver was largely unsuccessful in the small number of patient upon whom it was used.
The second maneuver was a single full contralateral roll. This second maneuver was similar to the first, except that the head was rotated the entire 360 degree turn from supine face up to supine face up, again turning toward the presumably unaffected ear.
The third maneuver was the iterative full contralateral roll. These exercises were performed once or twice in the clinic and the patient was encouraged to continue these at home for 7 days or until the symptoms subsided. The head was maintained in 30 degree flexion throughout the maneuver.
Epley8 describes treating horizontal canal HBPPV with a 360 degree xe2x80x9cbarrel rollxe2x80x9d away from the involved ear, keeping the horizontal canal in the earth vertical plane. To avoid dumping particles from the utricle back into the horizontal canal at the end of the procedure, the patient was returned to upright without first moving to the straight supine position. Epley notes that in the less agile patients, success can still be obtained by turning the head only 135 degrees from supine, opposite the involved ear.
Superior BPPV Treatments
Treatment maneuver to remove loosened otoconia from the superior (or anterior) semicircular canal has only been described by one author. Epley8 notes xe2x80x9cthe anterior canals can usually be cleared of canaliths by using the same positioning sequence as contralateral posterior canalithsxe2x80x9d.
BPPV Diagnostic
The classic clinical description of PBPPV includes rotary nystagmus in the effected ear down Dix-Hallpike position. Because head placement is difficult to describe in a manner that a non medical person could accurately and consistently perform, and because the accuracy of which posterior semicircular canal is not detected perfectly by the questionnaire, there will be described a device which will guide the user""s head into the right Dix-Hallpike and the left Dix-Hallpike positions. While in these positions the user can detect and understand which ear down causes the greatest amount of vertigo symptoms and hence which (right or left) post SCC is effected by the loosened otoconia. The ear which is effected is the ear which is initially placed downward in the treatment maneuver. That is, the treatment maneuver is effected-side-specific.
Based on this information and the fact that the studies of BPPV, response to head maneuvers all start from the knowledge of which ear is effected. A device to guide the user""s head into each of the two Dix Hallpike positions is described herein.
There are no prior art devices to this applicant""s knowledge which guide the user""s head into the Dix Hallpike positions for diagnostic purposes.
Historical Diagnosis and Treatment Systems
The historical method for diagnosing and treating BPPV is for the patient to visit his physician, be recognized as having vertigo and after some hopeful observation for spontaneous clearing and symptomatic treatment, be referred to an otolaryngologist (ear nose and throat specialist). This specialist would normally perform an involved history and a physical exam, a balance test (electronystagmogram), arrive at the diagnosis of BPPV, and manually perform a posterior canalith-repositioning maneuver (PCRP) for the patient. This PCRP will typically resolve 85-100% of the patients symptoms. This scenario presumes good efficiency on the part of each of the physicians and any technicians involved.
Questionnaire
BPPV has characteristic clinical findings that a patient can recognize. Because the clinical findings are easy to recognize, they can be successfully elicited by questionnaire. The results of these question answers can be statistically examined to determine the chance that Epley maneuver responsive BPPV is the origin of the patient""s vertigo, dizziness, or imbalance.
An original set of questions (DxQ) have been developed and the predictive value of each of the questions and question sets has been quantified such that the answers to the questions can be used to give a % chance that the user has BPPV.
Dizziness Handicap Inventory (DHI)16 is a series of 25 questions that have been written, tested and established as a method of measuring the physical, functional, and emotional effects of vertigo, dizziness or imbalance. This question series has been used to measure the severity of the user""s dizziness symptoms.
Patient responses to the DHI and DxQ questions were collected and correlated with the patient responsiveness to the Epley maneuvers. This correlation yielded proprietary information about the correlation of the DHI and DxQ question answers and Epley maneuver responsiveness and 2) proprietary information about the correlation of the DHI and DxQ question answers and posterior SCC crystal moving device success.
Computer Diagnostic History
Traditional medicine uses a medical personnel question system to elicit the patient""s history of symptoms combined with physical examination, laboratory findings and x-ray examinations to determine a diagnosis. Diagnoses are:related to treatments of varying success, and side effects.
With the advent of computer technology many attempts have been made to query patients (users) and/or medical personnel for combination of patient history, physical examination, laboratory findings, and x-ray findings to determine a diagnosis(DX) and to arrive at an appropriate treatment.
No computer system which will query a patient and render a diagnosis based on these questions have been successfully implemented. These have been unsuccessful because 1) the patient responses have not been satisfactorily systematized, 2) patient are either not careful or trained observers, 3) patient are not able to input the diagnostically necessary PE, lab or x-ray data, and 4) if responses can be obtained properly from the patient/user such that a diagnosis is established, treatment modalities typically require clearance by medical personnel. Based on these characteristics, medical diagnostic expert computer systems have been directed primarily for medical personnel use.
These medical diagnostic expert systems have not found a significant following among medical personnel. The lack of success is based on the time benefit ratio i.e. the value of the users time vs. the value to the medical personnel of the systems output. Also the users are able to work through the clinical problem without the computer dx (diagnostic) assistance.
There are multiple successful expert medical systems which address small areas within medicine. This invention addresses one such area in medical diagnosis, the diagnosis of BPPV. This invention identifies patients with classic BPPV within the group of patients who have vertigo/dizziness/imbalance.
Questionnaires in the Medical Literature
Many questionnaires have been used to either collect information from a patient efficiently for human mental analysis and use, or to analyze the public health conditions or the perspective of a community or to even screen those using the questionnaire for a certain condition which will then make the human treatment of those individuals more efficient or will detect those individuals in need of treatment by doctors such that they can be treated by doctors before their condition worsens i.e. make the ultimately necessary treatment more efficient17-25.
In 1965 Busis24 published a guide to dizziness/vertigo diagnosis. A section of that publication was devoted to disease characteristics and the differential diagnosis of vertigo. As a portion of his history of the vertigo patient, Busis pointed out that he could increase the clarity of his identifying patients with ear origin dizziness by broadening his questions to include symptoms that if present, automatically excluded the labyrinth as the sole problem. With this in mind he outlined a 4-section questionnaire. In the four sections of the questionnaire were 11, 12, 5, and 8 questions, respectively.
In 1967 Sheehy25 modified Busis"" questionnaire. Sheehy""s questionnaire was a 4-part questionnaire of 11, 14, 5, and 8 questions.
Both of these questionnaires were designed with the notion that the questionnaire xe2x80x9cfacilitated the matter of history taking in the case of the dizzy patientxe2x80x9d. The Busis and Sheehy questionnaires, although related directed to collecting information, were not directed to collecting that information for computational/diagnosis reasons, but rather to collecting information for making the physician""s history data collection more efficient. These 2 questionnaires do not directly impact on the current invention.
Vertigo Diagnostic Software in the Medical Literature
There have been 3 significant vertigo diagnostic computer software development efforts described in the medical literature. Each of these systems use patient history as an information source and each attempt to diagnose the origin of vertigo.
The first software effort is a program called Vertigo26-29. The effort to build this vertigo/dizziness/imbalance diagnostic system was begun in 1984 and is described in articles in 1987, 1988, and 1990. In the 1987 article, 150 patients are described; in the 1990 article 200 patients are described. The goal of this software was to provide an expert software system with which otolaryngology residents could hone their vertigo diagnostic skills and to serve as a resource for non-expert M.D.""s in the diagnosis of vertigo. The software is not intended for consumer use. The Vertigo system uses only patient history. It is based on Rutger""s University Expert system shell using Bayesian analysis techniques combined with a knowledge database.
The Vertigo software system uses a computer generated questionnaire, deals only with differentiating diseases of the inner ear, uses patient history only for diagnosis, and classifies diseases identified by the software as being inner ear in origin or being xe2x80x9cotherxe2x80x9d in origin, it does not focus significantly on BPPV. The criteria for the classification of these abnormalities is physician diagnosis based and not Epley procedure response based. The system does not use a device whatsoever to guide the patient through the canalith repositioning maneuver. The interface for this system is a complex interface of lists, yes/no answers, and multiple choices. From an output point of view the systems provides multiple differential diagnoses with a statistical probability of the patient having each differential diagnostic possibility.
The second vertigo diagnostic system is called ONE30-32. ONE was described in 1993, 1995, and 1996. Although the 1993 article describes the testing/developing of the ONE system with 173 patients, by 1996 the authors have tested and honed their system on 564 patients. The ONE system is specifically designed to be an intellectual assistant to the neurotologist (inner ear dizziness expert). ONE uses patient history, clinical examination findings, as well as test findings to predict the diagnosis for the patient""s dizziness or vertigo. The technique of determining the correct diagnosis has to do with what the authors call xe2x80x9ca new technique which outputs diagnosis probabilities.xe2x80x9d It is specifically designed to minimize wrong answers rather than specifically identify a correct answer. In this technique each question is weighted. Of the 142 patients clinical diagnoses analyzed by this system, 68 had acoustic neuromas and 63 had Meniere""s disease. The number of BPPV patients in the 142 patient samples was 3. This system is clearly not optimized for BPPV identification. The normal incidence of BPPV in 142 patients is 17%, or 44 patients.
The ONE system differs from the current invention in that it is directed to neurotologists and not patients. The questions have a complex number of options, yes/no, and multiple answers. The questions are not BPPV oriented as demonstrated by the limited number of cases of BPPV in the series. They do not use the Epley maneuver response as a definitive answer for the determination of the diagnosis of BPPV, but rather clinician diagnostic opinion. Finally, there is no device for guiding the patient""s head through a sequence of positions for accomplishing the Epley maneuver. This computer system has never been used in a commercially successful manner.
The third diagnostic program described in the medical literature is called Carrusel33. Carrousel had its start in 1987 and was originally described in 1990. This system""s stated goal is to be a xe2x80x9cpowerful educational tool for students and non-expert physiciansxe2x80x9d. The Carrousel system is a rule based diagnostic system which queries the patient.
Carrousel and the current invention both have computer-generated questions. They are dissimilar in that after the patient history is taken, the Carrousel system queries for lab test results as if the system were coaching an otolaryngology (ear nose and throat) resident (trainee) in an educational environment or as if it were coaching a non-expert physician in how to continue the work up of the patient. The authors state that most end organ vestibular problems are deduced and have no objective clinical confirmation. It would be my observation that BPPV has clear Dix Hallpike position induced rotary nystagmus and an Epley response is a clear clinical confirmation mechanism. Further dissimilarities are that Carrousel is not BPPV directed. They do not use an Epley maneuver as a definitive confirmation of their positional vertigo. There is no device for guiding the patient""s head through the maneuver either patient monitored or healthcare provider monitored. The Carrousel system is now 10 years old and has not been used commercially successfully.
2. Prior Art Patents
Several patents were found which describe systems which are significantly different from those described in this invention.
U.S. Pat. Nos. 5,471,382 and 5,764,923.
These patents describe a computer system in medical managed care in which a patient calls a medical management staff person. The patient relates his symptoms to the computer operator. The computer operator uses computer software utilizing xe2x80x9cbranch chain algorithm utilizing Bayes theoremxe2x80x9d to assign a risk category without diagnosis to the patient""s problem and to determine whether the patient needs to see a medical staff person and to what level of medical staff person the patient should be directed. The patient always has the computer operator between him and the computer questions. The system assigns risks and to what human healthcare resource the user is to be assigned. The system only directs the patient to one of several different human medical staff persons. There is no device central to the method of the patent. The patents make no mention of vertigo or positional vertigo.
U.S. Pat. No. 5,660,176
This patient describes a computer system which can be accessed by phone or by computer modem. The patent background makes clear that the most frequently seen 100 diagnoses are targeted. The user answers questions verbally or by tone phone keyboard. This system provides medical advice based on question answer determined common diagnosis. BPPV is not in the top 100 diagnoses. The user is not referred for head movement treatment. There is no device offered for sale in this patented system.
Prior Art Devices
A device for sale by Medical Surgical Innovations 1 Ocean Drive, Jupiter, Fla. consists of a combination of head band and skull vibrator.
The headband is worn around the head like a tennis sweat band. It is made from colorful neoprene and is of adjustable tension by varying the tightness of the attaching VELCRO(copyright) strip. Attached to the VELCRO(copyright) head band at the lateral side of the forehead on both sides in a plane parallel to the posterior semicircular canal on the same side is a small clear tube filled with water and containing a small amount of sand. This tube is intended to give the medical/paramedical person performing the maneuver for the patient, a visual feedback technique to see that the position sequence into which they are positioning the patient will cause the sand suspended in water to move around the tube of water in the same way that the loosened crystalline otoconia are being moved around and out of the posterior membranous semicircular canal. This device is intended for use by medical/paramedical personnel to judge the success of the positioning sequence that they are performing for the user.
The head band is used to hold a vibrator against the skull behind the effected ear for several minutes before and during the PCRP.
The skull vibrator is a small hand held, battery operated vibrator within a smooth plastic case. This vibrator was held against the mastoid surface behind the ear which was thought to be causing the BPPV symptoms.
Two authors (Epley8, Lempert12) have reported seating the patient in a device and completely rotating the patient in the plane of the posterior semicircular canal (with the capability to rotate the patient in the plane of any of the semicircular canals). These large devices represent the most accurate method of CRP for any of the canals. Ownership and self operation of these devices is certainly not feasible for the vast majority of patient suffering from BPPV.
The current invention provides a new process and system for the diagnosis and sale of devices for the treatment of BPPV. The current invention is directed to a medical diagnosis and treatment system in which in one embodiment the patient goes to a computer and answers a series of questions or is walked through the questions by another person. If the question answers indicate that the user has BPPV of one of the SCC""s, he is offered for sale or provided devices which 1) help in the diagnosis of which SCC is involved by the loosened crystals and 2) allows him to perform a head maneuver to move the loosened crystals out of the involved SCC. The user could be instructed to go to a provider of care for treatment of his BPPV. The two devices which perform diagnosis and treatment could be sold or used separately.
In another embodiment, the user could use the diagnostic questions to purchase the diagnostic portion of the device. With the diagnostic device findings entered into the question answer information, the statistical recommendation as to whether to purchase the treatment device would be more accurate.
In the preferred embodiment the user uses an electronic network (internet) to communicate with a central computer. The user answers a series of computer presented BPPV screening questions (DHI and DxQ). These questions are combined with the predictive value of each question answer and question set answer. Rule based decision making can be used or added to the statistical question analysis. The calculated chance that the user has Epley maneuver responsive BPPV is shared with the user.